阅读说明：本技术 一种硫掺杂石墨相氮化碳微管的制备方法 (Preparation method of sulfur-doped graphite-phase carbon nitride microtube ) 是由 王继刚 何忠秀 勾学军 于 2021-05-26 设计创作，主要内容包括：本发明涉及硫掺杂石墨相氮化碳微管的制备技术领域,尤其涉及一种硫掺杂石墨相氮化碳微管的制备方法,解决了现有技术中传统的热缩聚法制备硫(S)掺杂氮化碳时,存在制备周期长、工艺成本高,且制备过程中产生的H2S气体会造成环境污染的问题。一种硫掺杂石墨相氮化碳微管的制备方法,包括如下步骤：以富氮有机物为原料,以含硫有机物为硫源,通过自组装的方法形成含硫超分子前驱体；以碳纤维为微波吸收剂,将碳纤维与含硫超分子前驱体混合均匀后放入坩埚中,将坩埚置于微波谐振腔的中心。本发明制备周期短、工艺成本低,能够优化产物的电子结构与微观形貌,提高光催化活性；另一方面能够实现新型氮化碳的高效、绿色合成。(The invention relates to the technical field of preparation of sulfur-doped graphite-phase carbon nitride microtubules, in particular to a preparation method of a sulfur-doped graphite-phase carbon nitride microtubule, which solves the problems that the preparation period is long, the process cost is high and the H2S gas generated in the preparation process can cause environmental pollution when a traditional thermal polycondensation method is used for preparing sulfur (S) -doped carbon nitride in the prior art. A preparation method of a sulfur-doped graphite phase carbon nitride micropipe comprises the following steps: nitrogen-rich organic matters are used as raw materials, sulfur-containing organic matters are used as sulfur sources, and a sulfur-containing supermolecule precursor is formed by a self-assembly method; carbon fiber is used as a microwave absorbent, the carbon fiber and the sulfur-containing supramolecular precursor are uniformly mixed and then are placed into a crucible, and the crucible is placed in the center of a microwave resonant cavity. The preparation method has the advantages of short preparation period and low process cost, and can optimize the electronic structure and the micro morphology of the product and improve the photocatalytic activity; on the other hand, the efficient and green synthesis of the novel carbon nitride can be realized.)

1. A preparation method of a sulfur-doped graphite-phase carbon nitride micropipe is characterized by comprising the following steps: the method comprises the following steps: nitrogen-rich organic matters are used as raw materials, sulfur-containing organic matters are used as sulfur sources, and a sulfur-containing supermolecule precursor is formed by a self-assembly method; carbon fiber is used as a microwave absorbent, the carbon fiber and the sulfur-containing supramolecular precursor are uniformly mixed and then are placed into a crucible, the crucible is placed in the center of a microwave resonant cavity, and high-energy microwave irradiation heating is carried out after vacuumizing, so that the sulfur-doped graphite-phase carbon nitride microtubule is obtained.

2. The method for preparing the sulfur-doped graphite-phase carbon nitride microtube according to claim 1, wherein the supermolecule self-assembly process comprises the steps of dissolving nitrogen-rich organic matters and sulfur-containing organic matters in deionized water, magnetically stirring until the nitrogen-rich organic matters and the sulfur-containing organic matters are uniformly mixed, heating in a water bath at 60-90 ℃ for 2-5 hours, carrying out suction filtration and washing, then drying in a 60 ℃ oven, and grinding into powder to obtain the sulfur-containing supermolecule precursor.

3. The method for preparing the sulfur-doped graphite-phase carbon nitride microtube according to claim 2, wherein the nitrogen-rich organic substance is one of melamine, dicyandiamide and urea.

4. The method for preparing the sulfur-doped graphite phase carbon nitride microtube according to claim 2, wherein the sulfur-containing organic substance is one of trithiocyanic acid and thiourea.

5. The method for preparing the sulfur-doped graphite-phase carbon nitride microtube according to claim 2, wherein the molar ratio of the nitrogen-rich organic matter to the sulfur-containing organic matter is 1 (0.3-3).

6. The method for preparing the sulfur-doped graphite-phase carbon nitride microtubule as claimed in claim 2, wherein the mass ratio of the supramolecular precursor to the microwave absorbent is (10-50): 1.

7. The method for preparing the sulfur-doped graphite-phase carbon nitride microtube according to claim 2, wherein the degree of vacuum of the resonant cavity of the microwave oven is 5kPa, the high-energy microwave heating power is 2-6 kW, the heating temperature is 450-650 ℃, and the heating time is 5-20 min.

Technical Field

The invention relates to the technical field of preparation of a sulfur-doped graphite-phase carbon nitride micropipe, in particular to a preparation method of the sulfur-doped graphite-phase carbon nitride micropipe.

Background

With the rapid development of global industrialization and the large-scale growth of population, environmental pollution and energy crisis have become problems of general concern. Based on the problem, researchers are continuously dedicated to the research in the field of semiconductor photocatalysis for many years, and the semiconductor photocatalysis is applied to the aspects of degrading organic pollutants, decomposing water to prepare hydrogen and the like.

The graphite phase carbon nitride is a metal-free polymer semiconductor photocatalyst, and compared with the traditional semiconductor photocatalyst, the graphite phase carbon nitride photocatalyst has the advantages of no toxicity, no pollution, good physical and chemical stability, wide light absorption range, simple preparation process and the like. Can be obtained by thermal polycondensation of nitrogen-rich organic matters such as melamine, urea and the like, but the carbon nitride prepared by the method has low utilization rate of visible light because of high recombination rate of photon-generated carriers, low quantum efficiency and few active sites. Therefore, scientific researchers modify the elements by doping the elements, regulating and controlling the shape, constructing a heterojunction and the like so as to improve the photocatalytic activity. The carbon nitride is doped with nonmetal elements such as sulfur (S), phosphorus (P), boron (B), halogen atoms and the like, so that the visible light absorption of the carbon nitride can be enhanced, the carrier mobility is improved, and the separation of photon-generated electron-hole pairs is promoted, so that the photocatalytic activity is improved. However, when the sulfur (S) -doped carbon nitride is prepared by using the conventional thermal polycondensation method, the disadvantages of long preparation period, high process cost, environmental pollution caused by H2S gas generated in the preparation process and the like exist.

Disclosure of Invention

The invention aims to provide a preparation method of a sulfur-doped graphite-phase carbon nitride microtube, which solves the problems that the preparation period is long, the process cost is high and the environment pollution is caused by H2S gas generated in the preparation process when a traditional thermal polycondensation method is used for preparing sulfur (S) -doped carbon nitride in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a sulfur-doped graphite phase carbon nitride micropipe comprises the following steps: nitrogen-rich organic matters are used as raw materials, sulfur-containing organic matters are used as sulfur sources, and a sulfur-containing supermolecule precursor is formed by a self-assembly method; carbon fiber is used as a microwave absorbent, the carbon fiber and the sulfur-containing supramolecular precursor are uniformly mixed and then are placed into a crucible, the crucible is placed in the center of a microwave resonant cavity, and high-energy microwave irradiation heating is carried out after vacuumizing, so that the sulfur-doped graphite-phase carbon nitride microtubule is obtained.

Preferably, the supermolecule self-assembly process comprises the steps of dissolving the nitrogen-rich organic matter and the sulfur-containing organic matter in deionized water, stirring by magnetic force until the nitrogen-rich organic matter and the sulfur-containing organic matter are uniformly mixed, heating in a water bath for 2-5 hours at 60-90 ℃, carrying out suction filtration and washing, then drying in a 60 ℃ oven, and grinding into powder to obtain the sulfur-containing supermolecule precursor.

Preferably, the nitrogen-rich organic substance is one of melamine, dicyandiamide and urea.

Preferably, the sulfur-containing organic substance is one of trithiocyanic acid and thiourea.

Preferably, the molar ratio of the nitrogen-rich organic matter to the sulfur-containing organic matter is 1 (0.3-3).

Preferably, the mass ratio of the supermolecule precursor to the microwave absorbent is (10-50): 1.

Preferably, the vacuum degree of the resonant cavity of the microwave oven is 5kPa, the high-energy microwave heating power is 2-6 kW, the heating temperature is 450-650 ℃, and the heating time is 5-20 min.

The invention has at least the following beneficial effects:

1. the method has the advantages that raw materials are easy to obtain, the cost is low, a supermolecule precursor is prepared by a simple and environment-friendly self-assembly method, and a high-energy microwave irradiation heating technology is adopted to obtain the sulfur-doped graphite-phase carbon nitride microtubule with high catalytic activity, so that on one hand, the electronic structure and the micro-morphology of a product can be optimized, and the photocatalytic activity is improved; on the other hand, the method can realize the high-efficiency and green synthesis of novel carbon nitride and has very important significance for the practical application of the carbon nitride;

2. only water is used as a solvent in the preparation process, and reagents harmful to the environment such as organic solvents and the like are not used; the preparation process has no emission of waste gas and waste residue, and the process is environment-friendly and has no environmental pollution.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is an X-ray diffraction (XRD) pattern of the product obtained in example 1 with bulk carbon nitride;

FIG. 2 is an XPS spectrum of the product of example 1, wherein (a) is the full spectrum, (b) is the S2p peak and the fitted curve, (C) is the C1S peak and the fitted curve, and (d) is the N1S peak and the fitted curve;

FIG. 3 is a Scanning Electron Microscope (SEM) image of the product obtained in example 1;

FIG. 4 is a graphical representation of the specific surface area (BET) measurements of the product obtained in example 1 versus bulk carbon nitride;

FIG. 5 is a graph comparing the photocatalytic effects of the product obtained in example 1 and bulk-phase carbon nitride, wherein (a) is a degradation rate curve and (b) is a quasi-first order kinetic equation fitted curve.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example one

Weighing 1.77g of trithiocyanic acid and 1.26g of melamine (the molar ratio is 1:1), mixing and dissolving in 70mL of deionized water, magnetically stirring for 10min, heating to 80 ℃, carrying out water bath reaction for 3h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.09g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 4kW, heating to 550 ℃, keeping the temperature for 10min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

Fig. 1 is an XRD pattern of the resulting sulfur-doped carbon nitride microtube and bulk phase carbon nitride. The diffraction peak at 13.2 ° corresponds to the (100) crystal plane of carbon nitride, and corresponds to the distance between adjacent N holes in the heptazine ring repeating structural unit of carbon nitride in the same plane. The diffraction peak at 27.3 ° corresponds to the (002) crystal face, which is an interlaminar stacking peak of the aromatic substance, and it is confirmed that the product has a graphite-like layered structure, and the crystal structure of carbon nitride is not changed by doping.

FIG. 2 is an XPS spectrum of the resulting sulfur-doped carbon nitride microtube, and S2p can be fit to three peaks, the peaks at 162 and 163.8eV corresponding to the bond energy of C-S-C, indicating that the S element is incorporated into the crystal structure of carbon nitride by substituting a portion of the N element, and the peak at 168.3eV corresponding to the sulfur oxide formed during the reaction.

Fig. 3 is a Scanning Electron Microscope (SEM) image of the resulting sulfur-doped carbon nitride, resulting in a microtubular structure.

Fig. 4 is a plot comparing the resulting specific surface area (BET) analysis of sulfur-doped carbon nitride with that of bulk carbon nitride, and the microtubular morphology significantly increased the specific surface area of the sulfur-doped carbon nitride by about 13 times that of the bulk carbon nitride.

FIG. 5 is a comparison graph of the effect of photocatalytic degradation of rhodamine B by the obtained sulfur-doped carbon nitride microtubes and bulk carbon nitride, the degradation efficiency of the organic pollutant rhodamine B by the sulfur-doped carbon nitride is remarkably improved, and the quasi-first-order kinetic rate constant of the sulfur-doped carbon nitride is about 11 times that of bulk carbon nitride.

Example two

Weighing 2.65g of trithiocyanic acid and 1.26g of melamine (the molar ratio is 1.5:1), mixing and dissolving in 80mL of deionized water, magnetically stirring for 10min, heating to 80 ℃, carrying out water bath reaction for 3h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.06g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 2kW, heating to 450 ℃, keeping the temperature for 20min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

EXAMPLE III

Weighing 3.54g of trithiocyanic acid and 1.26g of melamine (the molar ratio is 2:1), mixing and dissolving in 90mL of deionized water, magnetically stirring for 10min, heating to 80 ℃, carrying out water bath reaction for 3h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.09g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 2kW, heating to 450 ℃, keeping the temperature for 20min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

Example four

Weighing 4.425g of trithiocyanic acid and 1.2g of melamine (the molar ratio is 2.5:1), mixing and dissolving in 100mL of deionized water, magnetically stirring for 10min, heating to 90 ℃, carrying out water bath reaction for 2h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.11g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 3kW, heating to 500 ℃, keeping the temperature for 15min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

EXAMPLE five

Weighing 2.28g of thiourea and 1.26g of melamine (the molar ratio is 3:1), mixing and dissolving in 70mL of deionized water, magnetically stirring for 10min, heating to 90 ℃, carrying out water bath reaction for 2h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.12g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 3kW, heating to 500 ℃, keeping the temperature for 15min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

EXAMPLE six

Weighing 1.77g of trithiocyanic acid and 1.89g of melamine (the molar ratio is 1:1.5), mixing and dissolving in 70mL of deionized water, magnetically stirring for 10min, heating to 70 ℃, reacting in a water bath for 4h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.15g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 4kW, heating to 550 ℃, keeping the temperature for 10min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

EXAMPLE seven

Weighing 1.77g of trithiocyanic acid and 3.15g of melamine (the molar ratio is 1:2.5), mixing and dissolving in 90mL of deionized water, magnetically stirring for 10min, heating to 70 ℃, reacting in a water bath for 4h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.18g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 5kW, heating to 600 ℃, keeping the temperature for 8min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

Example eight

Weighing 0.76g of thiourea and 1.68g of dicyandiamide (the molar ratio is 1:2), mixing and dissolving in 60mL of deionized water, magnetically stirring for 10min, heating to 60 ℃, carrying out water bath reaction for 5h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.2g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 5kW, heating to 600 ℃, keeping the temperature for 8min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

Example nine

Weighing 0.76g of trithiocyanic acid and 1.8g of urea (the molar ratio is 1:3), mixing and dissolving in 60mL of deionized water, magnetically stirring for 10min, heating to 60 ℃, carrying out water bath reaction for 5h, and drying to obtain the supramolecular precursor. And (3) uniformly mixing 3g of the precursor and 0.3g of carbon fiber, putting the mixture into a crucible, and covering the crucible with a crucible cover. And placing the crucible in the center of a microwave resonant cavity, vacuumizing to below 5kPa, starting microwaves, adjusting the power to 6kW, heating to 650 ℃, keeping the temperature for 5min, closing the microwaves, cooling to room temperature, and taking out a sample to obtain the sulfur-doped graphite-phase carbon nitride microtubule.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.